1. Field Of The Invention
The present invention relates to external sealing boots for enclosing and protecting various types of cable connections from environmental hazards and signal leakage.
2. General Background
In the field of telecommunications systems, signal leakage is a very undesirable emission (egress) of radio frequency or digital signals from within cable/connector interfaces and equipment utilized to carry the signals within telecommunications systems. Within the shielded space of the cable/connector interface and equipment, is the area in which the electromagnetic waves occur. If the shielding which is afforded in such a system is not efficient, or fails to prevent leakage, then some portion of these signals can leak out into the atmosphere. If such leakage is sufficiently severe, it will have the ability to blank out radio receivers, interfere with aircraft navigation systems, and interfere with other communication reception such as television.
On the other hand, if signal leakage occurs and is able to egress from the cable/connector interface, such signals can also enter or ingress thereinto. Therefore, there is a potential for over-the-air frequencies to penetrate into the cable/connector interface through such ingress. The most common causes for ingress is at the cable/connector interface, which is normally due to poor installation from home owners and the telecommunication personnel such as installers or technicians, and may be due to environmental conditions which may cause connectors to work themselves loose and allow ingress and egress of such signals.
The Federal Communications Commission (FCC) requires, in most cases, a signal leakage control program. Such a program is undertaken by routine monitoring and cumulative leakage index (CLI). In most cases, the cable/connector interface is the source of the signal leakage. Due to the problems associated with the interface, there is a major need to improve the RF and digital signals. There are several patents which have been found in the art, which address cable/connectors, to attempt to prevent water or other type of fluid flow into the connector. The most pertinent of the patents are as follows:
U.S. Pat. No. 4,173,385 issued to Fenn, et al. discloses a component of an overall claimed water-tight cable connector, a flexible boot having inner ribs along an extended end to seal to the outer sheath of a cable. The patent describes at the other end a lip engaging a flange on the collar of the connector to provide a water-tight seal.
Other patents disclose components that are integral to coaxial connectors.
U.S. Pat. No. 5,186,655 issued to Glenday, et al., discloses a connector in which the jacket of the coaxial cable is deformed to anchor and seal the connector.
U.S. Pat. No. 5,127,843, issued to Henry, et al., discloses as part of an integral connector, a connector having an insulated outer coupling shell covering an internal conductive shield or shell.
U.S. Pat. No. 4,540,230, issued to Iversen, et al., claims a connector which includes the use of O-rings or similar graphite seals and telescoping sleeves to provide for a sealed, insulated outer covering for the connector.
U.S. Pat. No. 4,605,274, issued to Ichikawa, discloses a connector having a hermetically sealed construction, and, further, having an internal construction within which the electrically connected elements which can move with respect to one another.
U.S. Pat. No. 4,869,679, issued to Szegda, discloses as part of a connector assembly, a stepped resilient sealing element clamped at one end to the connector and at the other end to the cable. See particularly FIG. 4, item 30 showing that the end of the sealing boot includes a circular lip which is received in an external circular recess in the cable sealing element.
U.S. Pat. No. 5,083,943, issued to Tarrant, discloses a CATV F connector in which a compressible gasket and a separator O-ring are claimed to provide continued shielding and weather-proofing for the connector.
U.S. Pat. No. 3,750,084, issued to Gardner, discloses as part of an external cap or boot on a high-tension connector, internal threads on the boot. These internal threads engage external threads on the connector to provide for sealing. Note that the seal must not be complete as a resilient O-ring, as additionally required, and that the O-ring, not the boot, forms the actual fluid tight seal.
In spite of the art cited, there continues to be the need for a product which can enhance the life of the cable/connector interface while together having certain mechanical and electrical benefits not found in the art.